Dual-Layer Black Matrix for Display Device Light Leakage
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Solution Overview
Problem
Existing display devices with non-straight edge black matrix layers suffer from charging issues, leading to abnormal image display and light leakage, especially when the distance between the black matrix layer and the active area is short, which degrades the display quality and interferes with GOA CLK signal lines.
Innovation Solution
A color filter substrate design featuring a first black matrix layer on one surface with opening areas corresponding to pixel elements and a second black matrix layer on the opposing surface, where the orthographic projection of the second black matrix layer covers a closed annular area, preventing charging and light leakage by overlapping with the first black matrix layer's projection, and maintaining a distance from GOA CLK signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the black matrix layer is designed with a non-straight edge to prevent charging, then the charging issue is alleviated, but light leakage occurs at the edge of the display device
Solution Approach 1:
The patent transitions from a single-layer black matrix design to a dual-layer configuration, where the first black matrix layer is on the array substrate and the second black matrix layer is on the color filter substrate. This dimensional change allows the black matrix structure to extend through the display device thickness, effectively blocking light leakage paths while maintaining the non-straight edge geometry for charging prevention.
Solution Approach 2:
The second black matrix layer is positioned to overlap with the projection of the first black matrix layer, creating a nested configuration where the two layers work together. The overlapping region forms a three-dimensional black matrix structure that simultaneously prevents charging and blocks light leakage, with the outer edge of the second layer extending beyond the first layer to address light leakage at the display edges.
2Length of moving object
If the distance between the black matrix layer and the active area is reduced to achieve narrower frame, then the frame width is reduced, but the black matrix layer couples with GOA CLK signal lines causing poor display
Solution Approach 1:
By extending the black matrix structure into the third dimension through the dual-layer configuration, the patent achieves effective signal line isolation with reduced horizontal spacing. The overlapping projection of the two black matrix layers creates a deeper shielding effect that prevents coupling with GOA CLK signal lines even when the lateral distance to the active area is minimized for narrow frame design.
3Reliability
If the black matrix layer is designed with non-straight edge segments, then charging is prevented, but manufacturing complexity increases
Solution Approach 1:
The black matrix structure is segmented into two separate layers: the first black matrix layer on the array substrate and the second black matrix layer on the color filter substrate. This segmentation allows each layer to be manufactured independently using standard photolithography processes, reducing the overall manufacturing complexity compared to creating a single complex non-straight edge structure.
Data Source
AI summary
The disclosure discloses a color filter substrate and a display device, where the color filter substrate includes a substrate including an active area and a peripheral area, there is such a first black matrix layer on a first surface of the substrate that has a part in the active area, there is a second black matrix layer on a second surface of the substrate facing away from the first surface; and an orthographic projection of the second black matrix layer onto the second surface, and an orthographic projection of the first black matrix layer onto the second surface, after they are overlapped with each other, covers the peripheral area of the color filter substrate; and the display device includes an array substrate, a liquid crystal layer, and the color filter substrate above.